ObesityOLFO-FOODNCT05869110
OLFactory Odour Stimulation and FOOD Preferences
A study testing Effects of odours on calorie intake, food choice and metabolic parameters in people with Obesity, run by University Hospital, Basel, Switzerland at 1 site in Switzerland.
Trial summary
The aim of the present "OLFO-FOOD" clinical trial is to investigate, if olfactory stimulation impacts food choice, reference and calorie intake in humans with obesity assessed using a test buffet. Read more about this study
- Who is it for?
- Ages 18 to 60 years
- Conditions the study is for
- Obesity
- What is being tested?
- Effects of odours on calorie intake, food choice and metabolic parameters
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 24 participants
- Where
- 1 siteSwitzerland
- Study dates
- 20 Apr 2023to 20 Aug 2024
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Age 18-60 years
- Written informed consent
- BMI ≥30 kg/m2
- Normosmia (as defined by Sniffin' Sticks Test)
Who cannot join
- Known allergy to olfactory stimulation substance, citrus fruits, citrus flavours, citrus food products
- Lactose-intolerance, celiac disease or non-celiac wheat sensitivity
- Diet other than omnivore or vegetarian
- Eating disorder (now or in the past)
- Dysphagia
- Acute disease affecting food intake
Show all 26Show fewer
- Acute upper respiratory tract infection, acute or chronic sinusitis
- Severe visual impairment (vision <10%)
- Surgical intervention of the nasal cavity or the paranasal sinus
- Current illicit drug abuse including daily marijuana and CBD (Cannabidiol) consumption (alcohol ≤2 drinks per day allowed)
- Any kind of severe chronic disease (e.g. severe heart failure, active cancer disease)
- Type 1 and 2 diabetes mellitus
- Treatment with insulin-sensitizing drugs within the last 3 months
- Treatment with Glucagon-like Peptide 1 (GLP1)-analoga
- History of neurodegenerative diseases, severe head trauma
- Severe renal impairment (e.g. estimated glomerular filtration rate <30 ml/min/m2)
- Known liver cirrhosis or other severe liver impairment
- Use of any kind of decongestant more than twice a week
- Uncontrolled dysthyroidism
- Uncontrolled hypertension
- Regular use of psychopharmaceutic drugs
- Study participants aims to start a new diet or exercise program during the study
- Bariatric surgery
- Pregnancy/Lactation
- Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc.
- Participation in an interventional study within the last 3 months
Trial locations and contacts
1 site in 1 country.
About this study
Official title: OLFO-FOOD: OLFactory Odour Stimulation and FOOD Preferences
The aim of the present "OLFO-FOOD" clinical trial is to investigate, if olfactory stimulation impacts food choice, reference and calorie intake in humans with obesity assessed using a test buffet.
Read the detailed description
Overweight study participants will be included in this study. For the participants the study consists of the screening visit and main visit 1 and 2. In between the main visits there is a wash-out period of 1 week (7 days ± 3 days). In total, participants will have 3 visits. After the screening visit and before the main visit 1, odours will be assigned in a randomized order. Each participant will receive both odours. The two visits (main visit 1 and 2) will have the exact same procedures except for the olfactory odour.
Hunger, appetite, thirst, food perception, nausea, headache and mood will be assessed and the first blood samples will be collected. The participants will receive the aspUraclip® filled with 50 μl of either olfactory stimulation or placebo (propylene glycol), due to the computer-generated randomization order. The "aspUraclip®" will be clipped to the nasal septum for 15 minutes. After olfactory stimulation, vital parameters will be measured and blood samples will be taken. Participants will rate hunger, appetite, thirst, nausea, headache, mood, as well as local nose irritation, odour intensity and odour perception. Directly afterwards, the participants choose food ad libitum from a test-buffet. Participants will have 2 hours to eat from the buffet, but can finish earlier if they wish. Eating time will be recorded. After finishing their meal, vitals will be measured, blood samples will be collected and the participants will rate hunger, appetite (general, carbohydrates, meat, dairy foods, vegetables, fruits, sweets, salty foods), thirst, nausea, headache, mood, food taste, food taste intensity, food scent intensity and food scent perception on a 10-point VAS (visual analogue scale). 2 hours after the start of the test-buffet, patients will rate the same questions on a VAS again, vitals and blood samples will be taken. If the participants eat throughout the 2-hour-timespan of the test-buffet and don't stop early, there will be only one measurement (vitals, VAS, BS) after 2 hours, when the test-buffet ends. Food intake will be measured by weighing the food before and after consumption. Following the test-buffet, patients will have a resting phase of 2 hours. During this phase, patients are free to read, listen to music or similar. After the 2 hour resting phase, vitals will be measured, blood samples collected and VAS-questions asked.
- Conditions
- Obesity
- Being tested
- Effects of odours on calorie intake, food choice and metabolic parameters
- Keywords
- olfactory stimulation, Hunger, Appetite, calorie intake, food choice, metabolic parameters
- Medical subject headings
- Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Effects of odours on calorie intake, food choice and metabolic parametersOther
Evaluation of the effects of olfactory stimulation compared to placebo on calorie intake and preference of food during a test-buffet.
Odours will be assigned in a randomized order. Each participant will receive both odours, in between there will be a wash-out period of 1 week.
| Study group | Role | What they receive |
|---|---|---|
| Experimental Intervention | Experimental | Olfactory stimulation Receives: Other: Effects of odours on calorie intake, food choice and metabolic parameters |
| Placebo | Placebo comparator | Propylene glycol Receives: Other: Effects of odours on calorie intake, food choice and metabolic parameters |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in calorie intake after olfactory stimulation
Olfactory stimulation compared to placebo in participants with obesity with a BMI ≥30 kg/m2 assessed by a test-buffet.
Measured: two time assessment at baseline and after 1 week
Secondary outcomes (10)
Change in food preference after olfactory stimulation
Olfactory stimulation compared to placebo in participants with obesity with a BMI ≥30 kg/m2 assessed by a test-buffet.
Proportion of carbohydrates, fat and protein of the chosen food products (processed foods, warmed-up ready-to-eat meal, fresh fruits and vegetables)
Measured: two time assessment at baseline and after 1 week
Change of hunger assessed via VAS (Visual Analogue Scale) upon olfactory stimulation
Hunger will be assessed via 10-point VAS Score (0= not at all, 10= maximum)) upon olfactory stimulation compared to placebo before and directly after olfactory stimulation, before and after exposure to a test-buffet.
Measured: up to eight time assessment from baseline till day 7
Change of appetite assessed via (Visual Analogue Scale) VAS upon olfactory stimulation
Appetite will be assessed via 10-point VAS Score (0= not at all, 10= maximum)) upon olfactory stimulation compared to placebo before and directly after olfactory stimulation, before and after exposure to a test-buffet.
Measured: up to eight time assessment from baseline till day 7
Change of thirst assessed via (Visual Analogue Scale) VAS upon olfactory stimulation
Thirst will be assessed via 10-point VAS Score (0= not at all, 10= maximum)) upon olfactory stimulation compared to placebo before and directly after olfactory stimulation, before and after exposure to a test-buffet.
Measured: up to eight time assessment from baseline till day 7
Change of nausea assessed via (Visual Analogue Scale) VAS upon olfactory stimulation
Nausea will be assessed via 10-point VAS Score (0= not at all, 10= maximum)) upon olfactory stimulation compared to placebo before and directly after olfactory stimulation, before and after exposure to a test-buffet.
Measured: up to eight time assessment from baseline till day 7
Change of headache assessed via (Visual Analogue Scale) VAS upon olfactory stimulation
Headache will be assessed via 10-point VAS Score (0= not at all, 10= maximum)) upon olfactory stimulation compared to placebo before and directly after olfactory stimulation, before and after exposure to a test-buffet.
Measured: up to eight time assessment from baseline till day 7
Change of mood assessed via (Visual Analogue Scale) VAS upon olfactory stimulation
Mood will be assessed via 10-point VAS Score (0= not at all, 10= maximum)) upon olfactory stimulation compared to placebo before and directly after olfactory stimulation, before and after exposure to a test-buffet.
Measured: up to eight time assessment from baseline till day 7
Change in plasma glucose Level (mmol/L)
Up to 5 blood samplings will be collected during each main visit, depending on the individual endpoint at the test-buffet: 4 blood samplings (60.8ml) if the participant eats the full 2 hours from the test-buffet, 5 samplings (76ml) if the participant stops eating from the test-buffet early.
- Before olfactory stimulation (OS), (Baseline)
- After OS, before the test-buffet (TB0)
- After individual endpoint at the test-buffet (TBX)
- After 2 hours of test-buffet (TB2)
- After 2 hours of resting phase (TBR)
Measured: up to 10 time assessment at visit one (Baseline, TB0, TBX, TB2, TBR) and after 1 week at visit 2 (Baseline TB0, TBX, TB2, TBR)
Change in plasma insulin Level (pmol/L)
Up to 5 blood samplings will be collected during each main visit, depending on the individual endpoint at the test-buffet: 4 blood samplings (60.8ml) if the participant eats the full 2 hours from the test-buffet, 5 samplings (76ml) if the participant stops eating from the test-buffet early.
- Before OS (Baseline)
- After OS, before the test-buffet (TB0)
- After individual endpoint at the test-buffet (TBX)
- After 2 hours of test-buffet (TB2)
- After 2 hours of resting phase (TBR)
Measured: up to 10 time assessment at visit one (Baseline, TB0, TBX, TB2, TBR) and after 1 week at visit 2 (Baseline TB0, TBX, TB2, TBR)
Change in serum cortisol Level (nmol/L)
Up to 5 blood samplings will be collected during each main visit, depending on the individual endpoint at the test-buffet: 4 blood samplings (60.8ml) if the participant eats the full 2 hours from the test-buffet, 5 samplings (76ml) if the participant stops eating from the test-buffet early.
- Before OS (Baseline)
- After OS, before the test-buffet (TB0)
- After individual endpoint at the test-buffet (TBX)
- After 2 hours of test-buffet (TB2)
- After 2 hours of resting phase (TBR)
Measured: up to 10 time assessment at visit one (Baseline, TB0, TBX, TB2, TBR) and after 1 week at visit 2 (Baseline TB0, TBX, TB2, TBR)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 May 2023
- Study start20 Apr 2023
- Primary completion31 Jul 2024
- Study completion20 Aug 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for ObesityStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Randomized, placebo-controlled, single-blind, cross-over, single-centre trial
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 24 participants (actual)
Sponsor and investigators
- Lead sponsor
- University Hospital, Basel, Switzerland
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Katharina Timper, Prof. Dr. med., Principal investigator, University Hospital, Basel, Switzerland
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05869110
- Sponsor's protocol ID
- 2023-00511, kt23Timper
- Other IDs
- 2023
- Acronym
- OLFO-FOOD
- Status last verified
- Dec 2024
- First submitted
- 11 May 2023
- Last updated
- 12 Dec 2024
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 12 Dec 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- OLFO-FOOD: OLFactory Odour Stimulation and FOOD Preferences
- ClinicalTrials.gov ID
- NCT05869110
- Acronym / sponsor ID
- OLFO-FOOD / 2023-00511, kt23Timper
- Conditions
- Obesity
- Keywords
- olfactory stimulation, Hunger, Appetite, calorie intake, food choice, metabolic parameters
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 24 participants (actual)
- Lead sponsor
- University Hospital, Basel, SwitzerlandUniversity, hospital or other
- Study start
- 20 Apr 2023 (actual)
- Primary completion
- 31 Jul 2024 (actual)
- Study completion
- 20 Aug 2024 (actual)
- First posted
- 22 May 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of the present "OLFO-FOOD" clinical trial is to investigate, if olfactory stimulation impacts food choice, reference and calorie intake in humans with obesity assessed using a test buffet.
Detailed description
Overweight study participants will be included in this study. For the participants the study consists of the screening visit and main visit 1 and 2. In between the main visits there is a wash-out period of 1 week (7 days ± 3 days). In total, participants will have 3 visits. After the screening visit and before the main visit 1, odours will be assigned in a randomized order. Each participant will receive both odours. The two visits (main visit 1 and 2) will have the exact same procedures except for the olfactory odour.
Hunger, appetite, thirst, food perception, nausea, headache and mood will be assessed and the first blood samples will be collected. The participants will receive the aspUraclip® filled with 50 μl of either olfactory stimulation or placebo (propylene glycol), due to the computer-generated randomization order. The "aspUraclip®" will be clipped to the nasal septum for 15 minutes. After olfactory stimulation, vital parameters will be measured and blood samples will be taken. Participants will rate hunger, appetite, thirst, nausea, headache, mood, as well as local nose irritation, odour intensity and odour perception. Directly afterwards, the participants choose food ad libitum from a test-buffet. Participants will have 2 hours to eat from the buffet, but can finish earlier if they wish. Eating time will be recorded. After finishing their meal, vitals will be measured, blood samples will be collected and the participants will rate hunger, appetite (general, carbohydrates, meat, dairy foods, vegetables, fruits, sweets, salty foods), thirst, nausea, headache, mood, food taste, food taste intensity, food scent intensity and food scent perception on a 10-point VAS (visual analogue scale). 2 hours after the start of the test-buffet, patients will rate the same questions on a VAS again, vitals and blood samples will be taken. If the participants eat throughout the 2-hour-timespan of the test-buffet and don't stop early, there will be only one measurement (vitals, VAS, BS) after 2 hours, when the test-buffet ends. Food intake will be measured by weighing the food before and after consumption. Following the test-buffet, patients will have a resting phase of 2 hours. During this phase, patients are free to read, listen to music or similar. After the 2 hour resting phase, vitals will be measured, blood samples collected and VAS-questions asked.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 2
- Model description
- Randomized, placebo-controlled, single-blind, cross-over, single-centre trial
| Arm | Type | Receives |
|---|---|---|
| Experimental Intervention | Experimental | Other: Effects of odours on calorie intake, food choice and metabolic parametersOlfactory stimulation |
| Placebo | Placebo comparator | Other: Effects of odours on calorie intake, food choice and metabolic parametersPropylene glycol |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Age 18-60 years
- Written informed consent
- BMI ≥30 kg/m2
- Normosmia (as defined by Sniffin' Sticks Test)
Key exclusion criteria (26 listed)
- Known allergy to olfactory stimulation substance, citrus fruits, citrus flavours, citrus food products
- Lactose-intolerance, celiac disease or non-celiac wheat sensitivity
- Diet other than omnivore or vegetarian
- Eating disorder (now or in the past)
- Dysphagia
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Effects of odours on calorie intake, food choice and metabolic parametersEvaluation of the effects of olfactory stimulation compared to placebo on calorie intake and preference of food during a test-buffet. Odours will be assigned in a randomized order. Each participant will receive both odours, in between there will be a wash-out period of 1 week. | Other | Experimental Intervention, Placebo |
Primary outcome
Change in calorie intake after olfactory stimulation
Time frame: two time assessment at baseline and after 1 week
Olfactory stimulation compared to placebo in participants with obesity with a BMI ≥30 kg/m2 assessed by a test-buffet.
10 secondary outcomes
Change in food preference after olfactory stimulation
Time frame: two time assessment at baseline and after 1 week
Change of hunger assessed via VAS (Visual Analogue Scale) upon olfactory stimulation
Time frame: up to eight time assessment from baseline till day 7
Change of appetite assessed via (Visual Analogue Scale) VAS upon olfactory stimulation
Time frame: up to eight time assessment from baseline till day 7
Change of thirst assessed via (Visual Analogue Scale) VAS upon olfactory stimulation
Time frame: up to eight time assessment from baseline till day 7
Change of nausea assessed via (Visual Analogue Scale) VAS upon olfactory stimulation
Time frame: up to eight time assessment from baseline till day 7
Change of headache assessed via (Visual Analogue Scale) VAS upon olfactory stimulation
Time frame: up to eight time assessment from baseline till day 7
Change of mood assessed via (Visual Analogue Scale) VAS upon olfactory stimulation
Time frame: up to eight time assessment from baseline till day 7
Change in plasma glucose Level (mmol/L)
Time frame: up to 10 time assessment at visit one (Baseline, TB0, TBX, TB2, TBR) and after 1 week at visit 2 (Baseline TB0, TBX, TB2, TBR)
Change in plasma insulin Level (pmol/L)
Time frame: up to 10 time assessment at visit one (Baseline, TB0, TBX, TB2, TBR) and after 1 week at visit 2 (Baseline TB0, TBX, TB2, TBR)
Change in serum cortisol Level (nmol/L)
Time frame: up to 10 time assessment at visit one (Baseline, TB0, TBX, TB2, TBR) and after 1 week at visit 2 (Baseline TB0, TBX, TB2, TBR)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Dec 2024.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Katharina Timper, Prof. Dr. med. principal investigator
University Hospital, Basel, Switzerland
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Effects of odours on calorie intake, food choice and metabolic parameters in people with Obesity, run by University Hospital, Basel, Switzerland at 1 site in Switzerland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 26 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 12 Dec 2024. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in calorie intake after olfactory stimulation (time frame: two time assessment at baseline and after 1 week). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Dec 2024.